I recently began shooting with a Canon 5D, moving up from the 30D body that I had been using. The major difference between the 5D and the 30D is that the 5D uses a full-frame sensor as opposed to the 30D’s APS-C sensor. Terms like “full-frame” and “APS-C” can be a bit confusing, so hopefully I can shed a little light on the subject with today’s post.

In digital cameras there is a sensor in place where the film used to be in film cameras. The light passing through the camera’s lens projects the image onto this sensor which then captures it digitally and records the image to memory. These sensors vary in size in both the number of pixels they contain (megapixels) and their physical dimension. Most digital SLR (single lens reflex) cameras bear a strong physical resemblance to the 35mm SLR’s we shot in decades past. But a difference between many of these cameras is the size of their sensor.

Taking Canon’s DSLR line for example, several of their cameras have an APS-C sensor which is smaller than a frame of 35mm film. The 30D model (a camera I use) has this size of sensor. Since the sensor is smaller it only records a portion of the image the lens is projecting. This results in a “zoomed in” effect on the captured image. On cameras with this size sensor, a photographer has to take the focal length of their lens and multiply it by 1.6 to see what the equivalent focal length is. My new 5D body, on the other hand, has a sensor that is the same size as a 35mm frame of film and therefore the equivalent focal length of the lens remains the same.

In the image above I took two pictures from the exact same location with a 30D and a 5D. I used the same lens (Canon 24-105 f/4L IS) on both photos at a focal length of 24mm. By overlaying 100% size images on top of each other you can see how much more of the scene is captured by the 5D’s full-frame sensor (the color 30D image is on top of the black & white 5D image).

Here is another example of the two images next to each other:

Top image taken with Canon 30D – Bottom image taken with Canon 5D

Notice how much more of the scene is captured with the 5D in the bottom image? The lens has a significantly greater wide-angle field of view. This is particularly helpful in landscape photography and architectural captures (not to mention my industry of real estate). The 1.6 crop factor sensor on the other hand can be a benefit when a photographer seeks added ‘reach’ for a lens. I recently used a 300mm lens with my 30D to photograph eagles and hawks in Farmington Utah. By putting this lens on the 1.6 crop camera, it became an equivalent of 480mm – a nice improvement.

In addition to the larger physical size of the sensor, the total amount of pixels is obviously different between the two. The 30D records an image of 3504 x 2336 pixels (8.2 megapixel) while the 5D records a 4368 x 2912 pixel (12.8 megapixel) image. This difference gives a noticeable quality boost to the 5D.

Both of these sensor types have their advantages and their applications. For the type of photography I shoot, I prefer the wide view and image quality of the 5D. The exception to this is when I need the added reach of the APS-C equipped 30D.

10 Comments

I really like Nikon. Back in the eighties, my primary cameras were a Nikon FE and FM2 with a considerable amount of glass. When I made the decision to re-enter photography in the digital age, I thought long and hard on which brand (Nikon or Canon) that I wanted to “marry”. I opted for Canon due to the quality and amount of lenses and accessories they offer. No regrets so far, though I am sure I would have been equally happy if I went with Nikon – except I would be with you in waiting for a full-frame body :)

I went with Canon because of a couple of reasons including the L series lens and they make the whole widget on the SLRs from the chips to the glass. Back on topic however, I’d love a full frame camera to upgrade from the 20d. The 5d is *almost* there. If Canon could add the dust shaker technology and some weather sealing to better compete with the Nikon D200, I’d be all over it. We’ll see what comes out later this year…

I too have been waiting and debating on the 5D or a future version. A full frame is in my future, but along with features and hoping for an improved nextgen sensor, it is tough to consider the cost when I am mostly a hobby photographer with only periodic professional work to justify it.

I went with the 5D because of the full frame not long after the XTi came out. My friend got the XTi and bragged about the built in dust shaker. Hmmm, it made me think. When it shakes (vibrates) the dust of the sensor, where does all that dust go? Reminds me of Tire Wear. Where does that all go?

Hi guys.I am wriring fom Italy.I guess the full frame will be the future despite the APS-C is now widely spread.No one seem thinks to the fact that in the past we already saw many format went fired, i think to the video standard.Of course i would like that Nikon enter asap in the full frame aren because the high quality, but also because the “natural” size of the frame vs the lenses. I mean the factor 1.5 or the best 1.3 for Leica M8 are still too much to properly use wides and tele (a wonderful 24 mm became a 36 mm…!)Thanks lot for those reading this post, and sorry if i committed some lingustic mistake.Bye Paolo

Hello, thank you for the clarity of your explanation. I agree with the previous posters, I am waiting for the replacement for the full frame 5D.

I’ve always been a Nikon user with a special interest in fast wideangle lenses. Nikon still haven’t provided a full frame camera to help me with this and I can’t wait anymore. I’ve just bought a Canon outfit, a cropped 400D to get me going while I build up my lens collection, but the next Canon I buy will have the full frame sensor.

Wideangle work with a cropped sensor is unsatisfactory as all the real wides for this format are slow, very slow.

Thank you so very much for posting this article.I currently have an EOS 300d and I myself prefer wide angled photography.

I was thinking of buying the canon eos 10-22mm Ef-s, i researched further and started reading about “Full Frame” sensors, i also read that the ef-s only work on the canon digital rebel / 10-30d range of cameras.

The thing that confused me most was comments about the canon ef 16-35mm having the same focal range (on a full frame camera) as the ef-s 10-22mm lens on the canon 300d.

Then i googled my question and blam this article came up completed answering all of my confusion.

Thanks again

Think i’m gonna go for the Canon 5d and get a new set of lenses / sell off my old camera.